Unescaping in functional pseudo loses information

[huyz]

Imagine if you have a functional pseudo with an escaped value, e.g. :contains("quoted\"value"), the parser will unescape the backslash and you end up with a value "quoted"value" where the double-quotes are indistinguishable. So information is lost and there is no way to go back to an equivalent string representation of the selector object.

[huyz]

There is also no way to have a closing parenthesis inside the value of a functional pseudo. None of the following works:
:contains(quoted)blah)
:contains("quoted)blah")
:contains("quoted)blah")